1. Field of the Invention
The present invention relates to an image forming optical system which can be used by combining with the solid-state imaging element of CCD, CMOS and the like. And it also relates to an image forming optical system which can be used for a miniature camera and a monitor camera and the like which are equipped in, for example, a digital still camera, a digital video camera, a cellular phone, PC and the like. Furthermore, the present invention also relates to an electronic instrument such as a digital still camera, a digital video camera, a cellular phone, PC and the like which use the image forming optical system.
2. Description of the Related Art
In recent years, electronic cameras for taking a photograph by using a solid-state imaging element like CCD and CMOS instead of using a silver salt film have become popular. In such electronic cameras, for an imaging unit which is equipped in a portable type computer or a cellular phone and the like, miniaturization and weight-lightening have been particularly demanded.